WO2018123020A1

WO2018123020A1 - Electromagnetic valve

Info

Publication number: WO2018123020A1
Application number: PCT/JP2016/089101
Authority: WO
Inventors: 拓也不二原
Original assignee: 三菱電機株式会社
Priority date: 2016-12-28
Filing date: 2016-12-28
Publication date: 2018-07-05

Abstract

A core (3) has a main body part (30) positioned on one axial-direction side of a plunger (17), and a tube part (31) that is shaped so as to protrude toward the plunger (17) from the main body part (30) and is capable of accommodating the plunger (17). The inner wall of the tube part (31) has a tapered part (34) of which the distal-end side has a large inside diameter and the side near the main body part (30) has a small inside diameter.

Description

solenoid valve

This invention relates to a solenoid valve.

The solenoid valve is kept closed by the load of the spring and is opened by thrust using electromagnetic force. An electromagnetic valve mounted on a vehicle like the electromagnetic valve according to Patent Document 1 is required to have high vibration resistance so as not to open due to vibration of the vehicle. Improvement of vibration resistance is achieved by increasing the load of the spring. On the other hand, since the valve opening performance must be maintained even when the load of the spring is increased, it is essential to improve the thrust for opening the valve.

Japanese Patent No. 4304877

There are a method of increasing the cross-sectional area of the magnetic circuit and a method of increasing the size of the coil as a method for improving the thrust of the valve opening. However, these methods have a problem of increasing the size and weight of the solenoid valve.

The present invention has been made to solve the above-described problems, and it is an object of the present invention to improve the valve opening thrust without increasing the size and weight of the solenoid valve.

The solenoid valve according to the present invention includes a plunger that reciprocates in the axial direction, a main body portion positioned on one side of the plunger in the axial direction, and a cylindrical portion that protrudes from the main body portion toward the plunger side and can accommodate the plunger. A coil that generates electromagnetic force that moves the plunger in the direction of the core, and a spring that moves the plunger in the direction opposite to the core, and the inner wall of the cylindrical portion has a large inner diameter on the tip side, It has a tapered portion with a small inner diameter on the main body side.

According to this invention, the inner wall of the cylindrical portion of the core is provided with the tapered portion having a large inner diameter on the front end side and a small inner diameter on the main body side, so that the amount of magnetic flux in the radial direction between the core and the plunger is reduced. And the amount of magnetic flux in the axial direction increases. As a result, the thrust of the valve opening can be improved without increasing the size and weight of the solenoid valve.

It is sectional drawing which shows the structural example of the solenoid valve which concerns on Embodiment 1 of this invention. It is a figure which shows the structural example of the engine with a turbocharger to which the solenoid valve which concerns on Embodiment 1 of this invention is applied, and shows the state at the time of accelerator on. It is a figure which shows the structural example of the engine with a turbocharger to which the solenoid valve which concerns on Embodiment 1 of this invention is applied, and shows the state at the time of an accelerator-off. It is a figure explaining the operation | movement method of the solenoid valve which concerns on Embodiment 1 of this invention, and shows a fully closed state. It is a figure explaining the operation | movement method of the solenoid valve which concerns on Embodiment 1 of this invention, and shows a full open state. It is an enlarged view of the cylinder part of the solenoid valve which concerns on Embodiment 1 of this invention, and its peripheral part. It is a figure which shows the reference example for helping the understanding of the solenoid valve which concerns on Embodiment 1 of this invention. FIG. 8A is a diagram for explaining the relationship between the stroke and thrust of the solenoid valve according to the reference example, and FIG. 8B is for explaining the relationship between the stroke and thrust of the solenoid valve according to Embodiment 1 of the present invention. It is a figure to do. It is an enlarged view of the cylinder part of the solenoid valve which concerns on Embodiment 2 of this invention, and its peripheral part. It is an enlarged view of the cylinder part and its peripheral part of a solenoid valve concerning Embodiment 3 of this invention. It is an enlarged view of the cylinder part and its peripheral part of a solenoid valve concerning Embodiment 4 of this invention. It is a modification of the solenoid valve concerning Embodiment 4 of this invention, and is an enlarged view of a cylinder part and its peripheral part. It is a modification of the solenoid valve concerning Embodiment 4 of this invention, and is an enlarged view of a cylinder part and its peripheral part.

Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing a configuration example of a solenoid valve 100 according to Embodiment 1 of the present invention. Here, Embodiment 1 will be described using an example in which electromagnetic valve 100 is mounted on a vehicle.
In the solenoid valve 100, a core assembly (hereinafter, "assembly" is referred to as "ASSY") 1 and a coil ASSY2 are joined. The core assembly 1 is formed by welding a core 3 that is a magnetic body and a yoke 4 that is a magnetic body by welding. The core 3 includes a columnar main body 30 and a cylindrical cylindrical portion 31 protruding from the main body 30.

The coil ASSY 2 includes a bobbin ASSY 6, a coil 7, a terminal 8, and a diode 9. The resin and the magnetic plate 5 are integrated by insert molding to form the bobbin ASSY 6. A coil 7 is wound around the bobbin ASSY 6. Thereafter, the coil 7 and the terminal 8 are joined by fusing, and the diode 9 is welded to the terminal 8.

The stator ASSY 11 is formed by integrating the core ASSY 1, the coil ASSY 2, and the bush 10 by insert molding. The peripheral portion of the terminal 8 in the stator assembly 11 forms a connector connected to the power source on the vehicle side. The non-magnetic pipe 12 is inserted into the plate 5 of the stator assembly 11. Subsequently, after the seal ring 13 is mounted on the holder 14, the holder 14 is press-fitted into the plate 5 side of the stator ASSY 11.

The valve assembly 16 includes a plunger 17, a spring 18, a valve 19, and a washer 20. A spring 18, a valve 19 and a washer 20 are inserted in this order into the plunger 17 which is a magnetic body, and held by caulking. Thereafter, a spring 15 is installed on the pipe 12 and a valve ASSY 16 is inserted into the stator ASSY 11. Finally, the O-ring 21 is mounted in the groove of the stator assembly 11.

When the assembly of all parts is completed, the solenoid valve 100 is attached to the piping of the vehicle by screws 23 passed through the bush 10 as shown in FIGS. Further, the O-ring 21 closes a gap between the solenoid valve 100 and the pipe to which the solenoid valve 100 is attached, and the air tightness of the pipe is ensured. Further, the connector of the power source 109 on the vehicle side and the connector of the stator ASSY 11 are connected.

Next, with reference to FIG. 2 and FIG. 3, the usage example of the solenoid valve 100 which concerns on Embodiment 1 is demonstrated. In this example, the electromagnetic valve 100 is used as an electrically controlled air bypass valve.
In the turbocharged engine shown in FIGS. 2 and 3, the solenoid valve 100 shown in FIG. 1 is attached to the air bypass passage 108 connecting the upstream side and the downstream side of the compressor 101 a of the turbocharger 101.

When the accelerator is on as shown in FIG. 2, the throttle valve 104 of the intake passage 103 is opened. Therefore, the air compressed by the compressor 101 a of the turbocharger 101 (hereinafter referred to as supercharged air) flows through the intercooler 105 and is carried to the engine 102. At this time, the electromagnetic valve 100 is closed.
A turbine 101b is mounted on the same axis as the compressor 101a. When the exhaust gas of the engine 102 flows through the exhaust passage 106 and rotates the turbine 101b, the compressor 101a also rotates. The exhaust passage 106 is provided with a waste gate valve 107 for adjusting the pressure of the exhaust gas.

When the accelerator shown in FIG. 3 is off, the throttle valve 104 is closed. Therefore, the supercharged air is accumulated in the intake passage 103. If the supercharged air is accumulated, the piping of the intake passage 103, the turbocharger 101, the engine 102, and the like may be damaged. Therefore, when the accelerator is off, the electromagnetic valve 100 is opened to prevent damage. When the solenoid valve 100 is opened, the air bypass passage 108 is opened, so that the supercharged air can be released from the downstream side to the upstream side of the compressor 101a.

Next, an operation method of the solenoid valve 100 according to the first embodiment will be described with reference to FIGS. 4 and 5. The solenoid valve 100 in FIG. 4 is in a fully closed state, and the solenoid valve 100 in FIG. 5 is in a fully open state.
As shown in FIGS. 4 and 5, the electromagnetic valve 100 is attached to the piping of the air bypass passage 108 on the vehicle side by screws 23. A part of the piping of the air bypass passage 108 is a valve seat 108a. Further, the terminal 8 of the electromagnetic valve 100 and the power source 109 on the vehicle side are electrically connected.

When the power source 109 is off, the solenoid valve 100 is fully closed as shown in FIG. Specifically, the valve ASSY 16 is urged by the spring 15 and the valve 19 is kept pressed against the valve seat 108a, and the air bypass passage 108 is closed. At this time, the plunger 17 of the valve assembly 16 also moves in the direction opposite to the core 3 while being guided by the pipe 12. The supercharged air enters the valve assembly 16 through the valve communication hole 22 of the valve 19 and pushes the seal ring 13 to contact the outer peripheral surface of the valve 19. As a result, the gap between the valve 19 and the seal ring 13 is closed, and leakage of supercharged air is prevented.
Incidentally, the spring 18 is a member for holding the valve 19 in a pressed state against the washer 20 in order to prevent the plunger 17 and the valve 19 from rattling. The diode 9 cuts a surge voltage generated when the power source 109 is turned off.

When the power source 109 is on, the solenoid valve 100 is fully opened as shown in FIG. Specifically, an electric current flows through the terminal 8 to the coil 7, and the coil 7, the core 3, the yoke 4, and the plate 5 serve as an electromagnet, and an electromagnetic force is generated. The plunger 17 is attracted to the core 3 side by electromagnetic force and is accommodated in the cylindrical portion 31. When the plunger 17 moves to the core 3 side while being guided by the pipe 12, the valve ASSY 16 is operated together with the plunger 17, the valve 19 is separated from the valve seat 108a, and the supercharged air is released to the upstream side of the compressor 101a.
Thus, when the electromagnetic valve 100 is opened and closed, the plunger 17 reciprocates in the axial direction.

Next, the core 3 of the electromagnetic valve 100 according to Embodiment 1 will be described with reference to FIG.
FIG. 6 is an enlarged view of the cylindrical portion 31 and its peripheral portion of the electromagnetic valve 100 according to the first embodiment. FIG. 6 shows the position of the plunger 17 when the electromagnetic valve 100 is at the intermediate opening. The intermediate opening is an intermediate opening between the fully closed position and the fully opened position, as shown in FIGS. 8A and 8B described later. The cylindrical portion 31 has a shape that protrudes from the main body portion 30 toward the plunger 17 and can accommodate at least a part of the plunger 17. The inner wall of the cylindrical portion 31 includes a first straight portion 32 having a constant inner diameter on the distal end side and a second straight portion 33 having a constant inner diameter on the main body portion 30 side. The inner diameter of the second straight portion 33 is smaller than the inner diameter of the first straight portion 32. Further, a tapered portion 34 is provided between the first straight portion 32 and the second straight portion 33. The tapered portion 34 has a large inner diameter on the tip end side of the cylindrical portion 31, and the inner diameter becomes smaller toward the main body portion 30 side. The maximum inner diameter of the taper portion 34 is the same as the inner diameter of the first straight portion 32, and the minimum inner diameter of the taper portion 34 is the same as the inner diameter of the second straight portion 33.

Next, effects (1) to (5) produced by the electromagnetic valve 100 according to Embodiment 1 will be described.
FIG. 7 is a diagram illustrating a reference example for helping understanding of the electromagnetic valve 100 according to the first embodiment. In the reference example, the straight portion 35 having a constant inner diameter is provided on all the inner walls of the cylindrical portion 31, and the tapered portion 34 is not provided.

(1) Thrust improvement In the case of the reference example shown in FIG. 7, the distance between the straight portion 35 of the cylindrical portion 31 and the plunger 17 is constant along the axial direction. The amount of magnetic flux in the direction is reduced. The amount of magnetic flux in the axial direction includes not only magnetic flux strictly in the axial direction but also magnetic flux closer to the axial direction than in the radial direction. In the figure, the direction of the magnetic flux is indicated by an arrow. The thicker the arrow, the greater the amount of magnetic flux, and the thinner the arrow, the smaller the amount of magnetic flux.
On the other hand, in the case of the first embodiment shown in FIG. 6, there is a magnetic flux that is closer to the axial direction than the radial direction from the plunger 17 toward the tapered portion 34. Therefore, the amount of magnetic flux in the axial direction is increased, and the amount of magnetic flux in the radial direction is reduced. By increasing the amount of magnetic flux in the axial direction, the thrust for moving the plunger 17 toward the core 3 is improved.

In FIG. 6, the position where the tapered portion 34 is provided is within the range of the intermediate opening of the solenoid valve 100, so that the thrust at the intermediate opening is particularly improved.
Moreover, in FIG. 6, the 1st straight part 32 is provided in the position near the plunger 17 when the solenoid valve 100 is a fully closed state. In the case of this configuration, the distance between the plunger 17 and the cylindrical portion 31 in the fully closed state is shorter than in the case where the tapered portion 34 is provided as it is to the tip of the cylindrical portion 31 without providing the first straight portion 32. . Therefore, the thrust when the plunger 17 starts moving in the valve opening direction is improved, and the initial movement of the plunger 17 becomes smooth.
Thereafter, when the plunger 17 moves toward the main body 30 and the distance between the plunger 17 and the main body 30 approaches, the amount of magnetic flux in the axial direction increases. Therefore, the taper part 34 does not need to be provided on the inner wall side of the cylindrical part 31 on the main body part 30 side, and the second straight part 33 is formed.

(2) Improving vibration resistance The solenoid valve 100 maintains a closed state by the load of the spring 15. As described above, when the valve opening thrust is improved, the load of the spring 15 can be increased. That is, the vibration resistance of the solenoid valve 100 is improved.

(3) Response improvement FIG. 8A is a diagram illustrating the relationship between the stroke and the thrust of the solenoid valve 100 according to the reference example illustrated in FIG. 7. FIG. 8B is a view for explaining the relationship between the stroke and the thrust of the solenoid valve 100 according to Embodiment 1 of the present invention. 8A and 8B also show the load of the spring 15.
As shown in FIG. 8A, the solenoid valve 100 according to the reference example has a stroke position where the thrust drops at the intermediate opening. The round frame in FIG. 8A indicates the stroke position where the thrust drops. At this stroke position, since the difference between the thrust and the load of the spring 15 is small, the responsiveness of the solenoid valve 100 is deteriorated. Responsiveness is the performance represented by the time required for the solenoid valve 100 to change from the fully closed state to the fully open state.
On the other hand, as shown in FIG. 8B, the solenoid valve 100 according to Embodiment 1 improves the drop in thrust at the intermediate opening by improving the valve opening thrust as described above. By improving the drop of the thrust, the difference between the thrust and the load of the spring 15 is increased, and the responsiveness is improved.

(4) Maintenance of layout In the past, there has been a method of increasing the sectional area of a magnetic circuit such as the yoke 4 or a method of increasing the size of the coil 7 in order to improve the thrust for valve opening. These methods lead to an increase in size and weight of the solenoid valve 100. Furthermore, the layout property when the electromagnetic valve 100 is mounted on a vehicle is deteriorated.
On the other hand, the solenoid valve 100 according to Embodiment 1 only needs to change the shape of the core 3. Since the solenoid valve 100 does not increase in size and does not increase in weight, the layout can be maintained.

(5) Prevention of cost increase When the cross-sectional area of the magnetic circuit such as the yoke 4 is increased or the size of the coil 7 is increased as in (4) above, the cost of the solenoid valve 100 is increased.
On the other hand, since the solenoid valve 100 according to Embodiment 1 only needs to change the shape of the core 3, it is possible to prevent an increase in cost.

As described above, the solenoid valve 100 according to Embodiment 1 includes the plunger 17 that reciprocates in the axial direction, the main body 30 that is positioned on one side of the plunger 17 in the axial direction, and the main body 30 that protrudes toward the plunger 17. The core 3 having a cylindrical portion 31 that can accommodate the plunger 17, the coil 7 that generates an electromagnetic force that moves the plunger 17 in the direction of the core 3, and the plunger 17 in the direction opposite to the core 3. The inner wall of the cylindrical portion 31 has a tapered portion 34 having a large inner diameter on the distal end side and a smaller inner diameter on the main body portion 30 side. With this configuration, the amount of magnetic flux in the radial direction between the core 3 and the plunger 17 is reduced, and the amount of magnetic flux in the axial direction is increased. Therefore, the valve opening thrust can be improved without increasing the size and weight of the solenoid valve 100.
In particular, the inner wall of the cylindrical portion 31 according to the first embodiment has a first straight portion 32 having a constant inner diameter on the distal end side and a second straight portion 33 having a constant inner diameter on the main body portion 30 side, A configuration in which the inner diameter of the second straight portion 33 is smaller than the inner diameter of the first straight portion 32, and a tapered portion 34 is provided between the first straight portion 32 and the second straight portion 33. It is. With this configuration, it is possible to improve the valve opening thrust at the intermediate opening.

In addition, although the structure which provided the 1st straight part 32 and the 2nd straight part 33 was shown in FIG. 6, it is not limited to this structure, Even if it is the structure which provided only any one Good.
When the first straight portion 32 having a constant inner diameter is provided on the distal end side of the inner wall of the cylindrical portion 31, the tapered portion 34 has an inner diameter that decreases from the first straight portion 32 toward the main body portion 30. In this case, the tapered portion 34 continues from the end portion of the first straight portion 32 until it reaches the main body portion 30.
Or when the 2nd straight part 33 with a constant internal diameter is provided in the main body part 30 side of the inner wall of the cylinder part 31, the internal diameter becomes large as the taper part 34 goes to the front end side from the 2nd straight part 33. . In this case, the tapered portion 34 continues from the end of the second straight portion 33 until it reaches the tip of the cylindrical portion 31.
As described above, when either the first straight portion 32 or the second straight portion 33 is provided on the inner wall of the cylindrical portion 31 and the tapered portion 34 is provided on the remaining portion of the inner wall, the opening is made as described above. The thrust of the valve can be improved.

Embodiment 2. FIG.
FIG. 9 is an enlarged view of the cylindrical portion 31 and its peripheral portion of the solenoid valve 100 according to Embodiment 2 of the present invention. 9, parts that are the same as or equivalent to those in FIGS. 1 to 8 of the first embodiment are given the same reference numerals, and descriptions thereof are omitted.
As shown in FIG. 9, in the second embodiment, the entire inner wall of the cylindrical portion 31 is a tapered portion 34. With this configuration, the effects (1) to (5) can be obtained as in the first embodiment.

Embodiment 3 FIG.
FIG. 10 is an enlarged view of the cylindrical portion 31 and its peripheral portion of the solenoid valve 100 according to Embodiment 3 of the present invention. 10, parts that are the same as or equivalent to those in FIGS. 1 to 8 of the first embodiment are given the same reference numerals, and descriptions thereof are omitted.
As shown in FIG. 10, in the third embodiment, a plurality of tapered portions 34 are provided on the inner wall of the cylindrical portion 31. In this example, five

taper portions

34 a, 34 b, 34 c, 34 d, 34 e are provided between the first straight portion 32 and the second straight portion 33. Each of the

tapered portions

34a, 34b, 34c, 34d, and 34e has a minimum inner diameter on the main body portion 30 side, and a maximum inner diameter on the distal end side of the cylindrical portion 31. When the inner wall of the cylindrical portion 31 is viewed from the radial direction of the plunger 17 as shown in FIG. 10, the five tapered

portions

34 a, 34 b, 34 c, 34 d, 34 e have a saw blade shape. The number of taper portions may be arbitrary. Moreover, the taper angle of each taper part may be the same, and a taper angle may differ for every taper part. Furthermore, only one of the first straight portion 32 and the second straight portion 33 may be provided, or the first straight portion 32 and the second straight portion 33 may not be provided.
With this configuration, the effects (1) to (5) can be obtained as in the first embodiment.

Embodiment 4 FIG.
FIG. 11 is an enlarged view of the cylindrical portion 31 and its peripheral portion of the solenoid valve 100 according to Embodiment 4 of the present invention. In FIG. 11, parts that are the same as or correspond to those in FIGS. 1 to 8 of the first embodiment are given the same reference numerals, and descriptions thereof are omitted.
As shown in FIG. 11, in the fourth embodiment, the outer wall of the plunger 17 is provided with a tapered portion 40 that tapers toward the core 3 side. The tapered portion 40 is a “second tapered portion”. In this example, the taper part 40 is provided in the edge part by the side of the core 3 among the outer walls of the plunger 17, and the 3rd straight part 41 with a constant outer diameter is provided in the remaining part of the outer wall. Conventionally, a corner of the end of the plunger 17 may be chamfered to provide a C surface or the like, but the tapered portion 40 is larger than the C surface. The tapered portion 40 may be provided on all the outer walls of the plunger 17.
Instead of providing the taper portion 34 in the core 3 as in the first to third embodiments, the case where the taper portion 40 is provided in the plunger 17 as in the fourth embodiment is also described in the first embodiment (1). The effects (5) to (5) can be obtained.
Although illustration is omitted, the taper portion 34 may be provided on the core 3 and the taper portion 40 may be provided on the plunger 17. Also in this case, the effects (1) to (5) described in the first embodiment can be obtained.

Here, a modified example of the tapered portion 40 of the plunger 17 will be described.
12 and 13 are modifications of the solenoid valve 100 according to Embodiment 4 of the present invention, and are enlarged views of the cylindrical portion 31 and its peripheral portion. 12 and 13, the same or corresponding parts as those in FIGS. 1 to 8 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
In the modification of FIG. 12, a fourth straight portion 42 having a constant outer diameter is provided on the outer wall of the plunger 17 on the core 3 side. The outer diameter of the fourth straight portion 42 is smaller than the outer diameter of the third straight portion 41. Further, a tapered portion 40 is provided between the third straight portion 41 and the fourth straight portion 42.
Also in this case, the effects (1) to (5) described in the first embodiment can be obtained. In addition, by setting the position where the tapered portion 40 is provided within the range of the intermediate opening of the solenoid valve 100, the thrust at the intermediate opening is improved.

In the modification of FIG. 13, a plurality of

taper portions

40 a, 40 b, and 40 c are provided on the outer wall of the taper portion 40. The number of taper portions may be arbitrary. Moreover, the angle of each taper part may be the same, and a taper angle may differ for every taper part. Furthermore, the 4th straight part 42 may be provided in the core 3 side of the taper part 40a.
Also in this case, the effects (1) to (5) described in the first embodiment can be obtained.

In the first to fourth embodiments, the outer wall of the cylindrical portion 31 is provided with a tapered portion that tapers from the main body portion 30 side toward the distal end side. However, the present invention is not limited to this. The shape of the outer wall may be arbitrary,

In the present invention, within the scope of the invention, free combinations of the respective embodiments, modification of arbitrary components of the respective embodiments, or omission of arbitrary components of the respective embodiments are possible.

Since the solenoid valve according to the present invention can increase the spring load and improve the vibration resistance by improving the thrust of the valve opening, the vibration resistance of an air bypass valve and an oil control valve mounted on the vehicle can be improved. Suitable for use in solenoid valves that require high performance.

1 core ASSY, 2 coil ASSY, 3 core, 4 yoke, 5 plate, 6 bobbin ASSY, 7 coil, 8 terminal, 9 diode, 10 bush, 11 stator ASSY, 12 pipe, 13 seal ring, 14 holder, 15 spring, 16 Valve ASSY, 17 Plunger, 18 Spring, 19 Valve, 20 Washer, 21 O-ring, 22 Valve communication hole, 23 Screw, 30 Body part, 31 Tube part, 32 First straight part, 33 Second straight part, 34, 34a to 34e, 40, 40a to 40c, taper portion, 35 straight portion, 41 third straight portion, 42 fourth straight portion, 100 solenoid valve, 101 turbocharger, 101a compressor, 101b tar Down, 102 engine, 103 an intake passage, 104 a throttle valve, 105 intercooler, 106 exhaust passage 107 waste gate valve, 108 an air bypass passage, 108a valve seat, 109 power supply.

Claims

A plunger that reciprocates in the axial direction;
A main body portion located on one side of the axial direction of the plunger, and a core having a cylindrical portion capable of accommodating the plunger in a shape protruding from the main body portion toward the plunger side;
A coil for generating an electromagnetic force for moving the plunger toward the core;
A spring that moves the plunger in a direction opposite to the core;
The solenoid valve according to claim 1, wherein the inner wall of the cylindrical portion has a tapered portion having a large inner diameter on the tip side and a small inner diameter on the main body side.
The inner wall of the cylindrical portion has a first straight portion having a constant inner diameter on the tip side and a second straight portion having a constant inner diameter on the main body portion side, and has an inner diameter of the first straight portion. The inner diameter of the second straight portion is smaller than that of the first straight portion, and the tapered portion is provided between the first straight portion and the second straight portion. solenoid valve.
The inner wall of the cylindrical portion has a first straight portion having a constant inner diameter on the tip side, and the tapered portion has an inner diameter that decreases from the first straight portion toward the main body portion. The solenoid valve according to claim 1.
The inner wall of the cylindrical portion has a second straight portion having a constant inner diameter on the main body portion side, and the tapered portion has an inner diameter that increases from the second straight portion toward the distal end side. The solenoid valve according to claim 1.
The solenoid valve according to claim 1, wherein an inner wall of the cylindrical portion has a plurality of the tapered portions.
The solenoid valve according to claim 1, wherein the outer wall of the plunger has a second taper portion that tapers toward the core side.
The turbocharger is installed in an air bypass passage connecting the upstream side and the downstream side of the compressor, and is used as an air bypass valve for returning the supercharged air on the downstream side of the compressor to the upstream side. Solenoid valve.
A plunger that reciprocates in the axial direction;
A main body portion located on one side of the axial direction of the plunger, and a core having a cylindrical portion capable of accommodating the plunger in a shape protruding from the main body portion toward the plunger side;
A coil for generating an electromagnetic force for moving the plunger toward the core;
A spring that moves the plunger in a direction opposite to the core;
The solenoid valve according to claim 1, wherein an outer wall of the plunger has a tapered portion that tapers toward the core side.